HueRok

2011 is250 with 105k miles.

I’ve been researching for a couple of weeks and have seen numerous threads about this topic. However I can’t seem to figure out what my problem is exactly.
This is what I’ve done:
Remove throttle body and thoroughly cleaned, replaced all spark plugs, cleaned pcv valve, cleaned MAF., inspected VVTs
Symptoms:
16 mpg, no check engine lights, sluggish acceleration, spitting(sounds almost like a miss)at warm idle and around 55-65 mph.

Sometimes it will act normal, but usually it’s lagging power and hesitates on acceleration. Even shifts aren’t acting normal

MikeFig82

iTrader: (13)

Check the evap purge valve. It could not be closing correctly. I had it go bad on me. It never threw a code as is was working intermittently. One way to check is pull the connector, then the hose that runs under the intake pipe. If its pulling vacuum with engine on it's not working. I had a idle miss and it was running like crap. Does your idle surge a little?
It may not be your problem, but it's an easy miss. If no check engine light on.

petersu33

Check your rear brakes, if they locked up you'll get bad mileage and poor throttle without any engine light.

HueRok

Thanks I will check it tomorrow. I do recall the spring on the hose connecting to the intake tube being a little loose(I could pull hose off). But I primed it apart to try and make spring tighten up. I really appreciate the input, and yes it seems to surge at times. But it sounds like a faint popping noise similar to a backfire. Especially at highway speeds.

HueRok

Good idea, however I have replaced all the pads within the past 2 months. The back left caliper was a PAIN to unfreeze. I read on here people had similar problems too.
It never fails, I can work on customers cars every day of the week but as soon as I work on my own I run across problems

Gville350

iTrader: (10)

No mention of any CELs. Any CELs? Sounds like a mis-fire to me too. Perhaps with new plugs, it could be a faulty coil pack.

2013FSport

iTrader: (2)

Sharing some possible / maybe worth checking ideas....
You could start by shooting an IR gun at the CATs. If plugged it won't make any power although it may be able to REV it won't do much work like actually moving the car.
Point that same gun at each flange of the exhaust manifold and see if any cylinder is lower/higher temp than the rest too.

Although I think you'd have a code(s) if these were failing, grab your OBD reader and scan fuel trims, load vs ignition advance and fuel pressure at the rail. If for some reason its holding the ignition advance back (bad knock sensor) that could be an issue as well as low fuel pressure.
The App Torque pro can gather this info pretty quick for cheap if you have an Elm bluetooth device.

HueRok

Thanks for everyone’s input. So yesterday I checked the purge valve and found that not to be the culprit. From there I took some MAF sensor cleaner and sprayed it cautiously around areas that could show slight vacuum leaks (2nd attempt)— Nothing. So I decided to break out my trusty little OBD scanner($20 Internet special) to see if I could catch any misfires as i did before changing plugs— Once again nothing. However, I did noticed that one of the O2 sensors wasn’t reading any voltage at first, and then a couple minutes later it WAS. Noticing this, I thought they maybe it’s just not reading right due to being dirty?? Out of desperation, I took the leftover half bottle of seafoam and saturated all the areas that drew vacuums on top of engine since originally I only went through the throttle body.
I immediately noticed some pretty bad popping and smoke. After heatsoaking for about 10 minutes, I drove it hard On my way home from work (approximately 30 miles).
—knock on wood, the car drove better than it had in months. Still too early to verify, but I’m hoping that I just didn’t clean it out good enough the first time, and I remember I only drove it for about 10-15 minutes originally before parking it for awhile...

ill be sure ite to keep you all posted in the coming days.

HueRok

So after a couple of days of commuting to and from my body shop (30 miles one way), I’ve come to the conclusion that the seafoam treatment has cleaned up my problem. I believe one of the oxygen sensors was getting a “dirty” reading causing my issues. I’m averaging 29mpg——up from my previous average of 27 before this last cleaning.

MikeFig82

iTrader: (13)

I'm assuming you just had some carbon build up. Maybe next oil change before. Do a full seafoam to the vac lines.

shadyfISF

Hello,

Did your fix resolve the problem? If so, which O2 sensor was it? Believe there are 2?

Thanks,

Peter